trace-cmd: Add trace-cmd report --version to extract version info

Now that the trace.dat file can save the version of the executable that was
used to create it, save that information. This will be useful if a user has
a problem with a trace.dat file. It can let the developers know what version
was used to create it. We need a way to extract this information. Adding a
new "--version" to trace-cmd report will display the saved version in the
trace.dat file if it exists.

Link: http://lore.kernel.org/linux-trace-devel/20190610212706.2505bffe@oasis.local.home

Reviewed-by: Slavomir Kaslev <kaslevs@vmware.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

5 files changed, 37 insertions, 0 deletions

diff --git a/Documentation/trace-cmd-report.1.txt b/Documentation/trace-cmd-report.1.txt
index 20d6b7ab..87f4d7a1 100644
--- a/Documentation/trace-cmd-report.1.txt
+++ b/Documentation/trace-cmd-report.1.txt
@@ -248,6 +248,10 @@ OPTIONS
     If the trace.dat file recorded uname during the run, this will retrieve that
     information.
 
+*--version*::
+    If the trace.dat file recorded the version of the executable used to create
+    it, report that version.
+
 *--ts-offset* offset::
     Add (or subtract if negative) an offset for all timestamps of the previous
     data file specified with *-i*. This is useful to merge sort multiple trace.dat
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 8b922102..6f62ab99 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -138,6 +138,7 @@ int tracecmd_init_data(struct tracecmd_input *handle);
 
 void tracecmd_print_stats(struct tracecmd_input *handle);
 void tracecmd_print_uname(struct tracecmd_input *handle);
+void tracecmd_print_version(struct tracecmd_input *handle);
 
 struct tep_record *
 tracecmd_read_page_record(struct tep_handle *pevent, void *page, int size,
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 264e3c32..61566bad 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -94,6 +94,7 @@ struct tracecmd_input {
 	double			ts2secs;
 	char *			cpustats;
 	char *			uname;
+	char *			version;
 	struct input_buffer_instance	*buffers;
 	int			parsing_failures;
 
@@ -2220,6 +2221,9 @@ static int handle_options(struct tracecmd_input *handle)
 		case TRACECMD_OPTION_UNAME:
 			handle->uname = strdup(buf);
 			break;
+		case TRACECMD_OPTION_VERSION:
+			handle->version = strdup(buf);
+			break;
 		case TRACECMD_OPTION_HOOK:
 			hook = tracecmd_create_event_hook(buf);
 			hook->next = handle->hooks;
@@ -2599,6 +2603,21 @@ void tracecmd_print_uname(struct tracecmd_input *handle)
 }
 
 /**
+ * tracecmd_print_uname - prints the recorded uname if it was recorded
+ * @handle: input handle for the trace.dat file
+ *
+ * Looks for the option TRACECMD_OPTION_VERSION and prints out what's
+ * stored there, if it is found. Otherwise it prints that none were found.
+ */
+void tracecmd_print_version(struct tracecmd_input *handle)
+{
+	if (handle->version)
+		printf("%s\n", handle->version);
+	else
+		printf(" version was not recorded in this file\n");
+}
+
+/**
  * tracecmd_hooks - return the event hooks that were used in record
  * @handle: input handle for the trace.dat file
  *
diff --git a/tracecmd/trace-read.c b/tracecmd/trace-read.c
index dbfb3a54..d22c723b 100644
--- a/tracecmd/trace-read.c
+++ b/tracecmd/trace-read.c
@@ -1112,6 +1112,7 @@ enum output_type {
 	OUTPUT_NORMAL,
 	OUTPUT_STAT_ONLY,
 	OUTPUT_UNAME_ONLY,
+	OUTPUT_VERSION_ONLY,
 };
 
 static void read_data_info(struct list_head *handle_list, enum output_type otype,
@@ -1160,6 +1161,8 @@ static void read_data_info(struct list_head *handle_list, enum output_type otype
 			continue;
 		case OUTPUT_UNAME_ONLY:
 			tracecmd_print_uname(handles->handle);
+		case OUTPUT_VERSION_ONLY:
+			tracecmd_print_version(handles->handle);
 			continue;
 		}
 
@@ -1386,6 +1389,7 @@ static void add_hook(const char *arg)
 }
 
 enum {
+	OPT_version	= 238,
 	OPT_tsdiff	= 239,
 	OPT_ts2secs	= 240,
 	OPT_tsoffset	= 241,
@@ -1427,6 +1431,7 @@ void trace_report (int argc, char **argv)
 	int show_page_size = 0;
 	int show_printk = 0;
 	int show_uname = 0;
+	int show_version = 0;
 	int latency_format = 0;
 	int show_events = 0;
 	int print_events = 0;
@@ -1468,6 +1473,7 @@ void trace_report (int argc, char **argv)
 			{"debug", no_argument, NULL, OPT_debug},
 			{"profile", no_argument, NULL, OPT_profile},
 			{"uname", no_argument, NULL, OPT_uname},
+			{"version", no_argument, NULL, OPT_version},
 			{"by-comm", no_argument, NULL, OPT_bycomm},
 			{"ts-offset", required_argument, NULL, OPT_tsoffset},
 			{"ts2secs", required_argument, NULL, OPT_ts2secs},
@@ -1618,6 +1624,9 @@ void trace_report (int argc, char **argv)
 		case OPT_uname:
 			show_uname = 1;
 			break;
+		case OPT_version:
+			show_version = 1;
+			break;
 		case OPT_bycomm:
 			trace_profile_set_merge_like_comms();
 			break;
@@ -1767,6 +1776,9 @@ void trace_report (int argc, char **argv)
 	/* yeah yeah, uname overrides stat */
 	if (show_uname)
 		otype = OUTPUT_UNAME_ONLY;
+	/* and version overrides uname! */
+	if (show_version)
+		otype = OUTPUT_VERSION_ONLY;
 	read_data_info(&handle_list, otype, global);
 
 	list_for_each_entry(handles, &handle_list, list) {
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index d2a10895..00127299 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -166,6 +166,7 @@ static struct usage_help usage_help[] = {
 		"          --check-events return whether all event formats can be parsed\n"
 		"          --stat - show the buffer stats that were reported at the end of the record.\n"
 		"          --uname - show uname of the record, if it was saved\n"
+		"          --version - show version used to build the trace-cmd exec that created the file\n"
 		"          --profile report stats on where tasks are blocked and such\n"
 		"          -G when profiling, set soft and hard irqs as global\n"
 		"          -H Allows users to hook two events together for timings\n"